1. Field of the Invention
The invention relates to a hydrogen generating apparatus and a fuel cell using the same. More particularly, the invention relates to a hydrogen generating apparatus using a solid fuel, and a fuel cell using the hydrogen generating apparatus.
2. Description of Related Art
A fuel cell (FC) is a power generator in which chemical energy is directly converted into electrical power through electrochemical reaction. Compared to a conventional power generating method, the fuel cell has advantages of low pollution, low noise, high energy density and higher energy conversion rate, etc., which is a clean energy source with a prospective future, and may be applied in various domains such as mobile electronic products, home power generation systems, transportation tools, military equipments, space industry, and small-scale power generation systems etc.
Various fuel cells may have different application domains due to their different operation principles and different operation environments. Proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) are mainly used in mobile energy applications, which are all low-temperature activation type fuel cells using the proton exchange membrane to carry on the proton conduction mechanism. An operation principle of the PEMFC is that the hydrogen carries on an oxidation reaction at an anode catalyst layer to generate hydrogen ions (H+) and electrons (e−) (PEMFC principle), or the methanol and water carry on the oxidation reaction at the anode catalyst layer to generate hydrogen ions (H+), carbon dioxide (CO2) and electrons (e−) (DMFC principle), wherein the hydrogen ions may be conducted to a cathode through the proton exchange membrane, and the electrons are first transmitted to a load through an external circuit to work, and then are transmitted to the cathode. Now, the oxygen provided to the cathode and the hydrogen ions and the electrons carry on a reduction reaction at a cathode catalyst layer to generate water. The hydrogen fuel required by the above anode may be obtained through a solid sodium borohydride (NaBH4) hydrogen storage technology, by which water is added to the solid sodium borohydride for reaction, so as to generate the hydrogen.
The reaction between the solid sodium borohydride and the water is one-off reaction, namely, once the reaction is carried on, it is stopped only when the solid sodium borohydride or the water is used out. Therefore, how to achieve a stepwise reaction is a problem to be resolved.